Information relative to the source and fate of the inorganic pyrophosphate in plasma, joint fluid, and articular tissues is being collected relative to the pathogenesis of calcium pyrophosphate dihydrate crystal deposits in articular cartilage. Factors promoting or interferring with the solubility of these and the monosodium urate monohydrate crystals of gout are being sought and characterized as are substances which bind to such crystals from plasma, synovial fluid and extracts of joint tissues. The ultimate goal is to discover how to prevent and/or remove these particles from their sites of deposition.